If on a market price the difference of selling price with a discount of 30% and two successive discounts of 20% and 10% is 72, then the marked price ( in rupees ) is ?

Answer: Option A

Let the marked price = Rs. x
Single Discount = 30%
Two successive discount is equivalent
$$\begin{array}{rl}& \text{= }\left(20+10-\frac{20\times 10}{100}\right)\%\\ & =\left(30-2\right)\%\\ & =28\%\end{array}$$
Difference = 2%
According to the question,
$$\begin{array}{rl}& \Rightarrow \text{2}\%\text{ of }x\text{ = 72}\\ & \Rightarrow \frac{2}{100}\times x=72\\ & \Rightarrow x=\frac{72\times 100}{2}\\ & \Rightarrow x=\text{Rs}\text{. 3600}\end{array}$$